Answer:
Step-by-step explanation:
to solve this problem we can use the Pythagorean theorem
UT and TL are the legs, while LU is the hypotenuse
We have to find LU so we can proceed like this
x^2 + (x+1)^2 = LU^2
x^2 + x^2 + 1 + 2x = LU^2
2x^2 + 2x + 1 = LU^2
LU = +/- 
we have to take only the positive value because a length can’t be negative.
2x^2 + 2x + 1 is positive for every value of x, so the final answer is

the answer would be C
because it is taking the total hours ( x) and subtracting 1 ( the first hour that cost $7
and then multiplying x by the $5 per minute and then adding the $7 for the first hour
Notice, it has a square base, so the base or bottom of the rectangular prism, is a square, that means, length = width = x, length and width both have the same value, let's say "x", check the picture below